/*
 * $Id: JSONValue.java,v 1.1 2006/04/15 14:37:04 platform Exp $
 * Created on 2006-4-15
 */
package org.json.simple;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.Writer;
import java.util.List;
import java.util.Map;

import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

/**
 * @author FangYidong<fangyidong@yahoo.com.cn>
 */
public class JSONValue {
    /**
     * Parse JSON text into java object from the input source. Please use
     * parseWithException() if you don't want to ignore the exception.
     * 
     * @see org.json.simple.parser.JSONParser#parse(Reader)
     * @see #parseWithException(Reader)
     * 
     * @param in
     * @return Instance of the following: org.json.simple.JSONObject,
     *         org.json.simple.JSONArray, java.lang.String, java.lang.Number,
     *         java.lang.Boolean, null
     * 
     */
    public static Object parse(Reader in)
    {
        try
        {
            JSONParser parser = new JSONParser();
            return parser.parse(in);
        }
        catch (Exception e)
        {
            return null;
        }
    }

    public static Object parse(String s)
    {
        StringReader in = new StringReader(s);
        return parse(in);
    }

    /**
     * Parse JSON text into java object from the input source.
     * 
     * @see org.json.simple.parser.JSONParser
     * 
     * @param in
     * @return Instance of the following: org.json.simple.JSONObject,
     *         org.json.simple.JSONArray, java.lang.String, java.lang.Number,
     *         java.lang.Boolean, null
     * 
     * @throws IOException
     * @throws ParseException
     */
    public static Object parseWithException(Reader in) throws IOException, ParseException
    {
        JSONParser parser = new JSONParser();
        return parser.parse(in);
    }

    public static Object parseWithException(String s) throws ParseException
    {
        JSONParser parser = new JSONParser();
        return parser.parse(s);
    }

    /**
     * Encode an object into JSON text and write it to out.
     * <p>
     * If this object is a Map or a List, and it's also a JSONStreamAware or a
     * JSONAware, JSONStreamAware or JSONAware will be considered firstly.
     * <p>
     * DO NOT call this method from writeJSONString(Writer) of a class that
     * implements both JSONStreamAware and (Map or List) with "this" as the
     * first parameter, use JSONObject.writeJSONString(Map, Writer) or
     * JSONArray.writeJSONString(List, Writer) instead.
     * 
     * @see org.json.simple.JSONObject#writeJSONString(Map, Writer)
     * @see org.json.simple.JSONArray#writeJSONString(List, Writer)
     * 
     * @param value
     * @param writer
     */
    @SuppressWarnings("unchecked")
    public static void writeJSONString(Object value, Writer out) throws IOException
    {
        if (value == null)
        {
            out.write("null");
            return;
        }

        if (value instanceof String)
        {
            out.write('\"');
            out.write(escape((String) value));
            out.write('\"');
            return;
        }

        if (value instanceof Double)
        {
            if (((Double) value).isInfinite() || ((Double) value).isNaN())
                out.write("null");
            else
                out.write(value.toString());
            return;
        }

        if (value instanceof Float)
        {
            if (((Float) value).isInfinite() || ((Float) value).isNaN())
                out.write("null");
            else
                out.write(value.toString());
            return;
        }

        if (value instanceof Number)
        {
            out.write(value.toString());
            return;
        }

        if (value instanceof Boolean)
        {
            out.write(value.toString());
            return;
        }

        if ((value instanceof JSONStreamAware))
        {
            ((JSONStreamAware) value).writeJSONString(out);
            return;
        }

        if ((value instanceof JSONAware))
        {
            out.write(((JSONAware) value).toJSONString());
            return;
        }

        if (value instanceof Map)
        {
            JSONObject.writeJSONString((Map<String, Object>) value, out);
            return;
        }

        if (value instanceof List)
        {
            JSONArray.writeJSONString((List<Object>) value, out);
            return;
        }

        out.write(value.toString());
    }

    /**
     * Convert an object to JSON text.
     * <p>
     * If this object is a Map or a List, and it's also a JSONAware, JSONAware
     * will be considered firstly.
     * <p>
     * DO NOT call this method from toJSONString() of a class that implements
     * both JSONAware and Map or List with "this" as the parameter, use
     * JSONObject.toJSONString(Map) or JSONArray.toJSONString(List) instead.
     * 
     * @see org.json.simple.JSONObject#toJSONString(Map)
     * @see org.json.simple.JSONArray#toJSONString(List)
     * 
     * @param value
     * @return JSON text, or "null" if value is null or it's an NaN or an INF
     *         number.
     */
    @SuppressWarnings("unchecked")
    public static String toJSONString(Object value)
    {
        if (value == null)
            return "null";

        if (value instanceof String)
            return "\"" + escape((String) value) + "\"";

        if (value instanceof Double)
        {
            if (((Double) value).isInfinite() || ((Double) value).isNaN())
                return "null";
            else
                return value.toString();
        }

        if (value instanceof Float)
        {
            if (((Float) value).isInfinite() || ((Float) value).isNaN())
                return "null";
            else
                return value.toString();
        }

        if (value instanceof Number)
            return value.toString();

        if (value instanceof Boolean)
            return value.toString();

        if ((value instanceof JSONAware))
            return ((JSONAware) value).toJSONString();

        if (value instanceof Map)
            return JSONObject.toJSONString((Map<String, Object>) value);

        if (value instanceof List)
            return JSONArray.toJSONString((List<Object>) value);

        return value.toString();
    }

    /**
     * Escape quotes, \, /, \r, \n, \b, \f, \t and other control characters
     * (U+0000 through U+001F).
     * 
     * @param s
     * @return
     */
    public static String escape(String s)
    {
        if (s == null)
            return null;
        StringBuffer sb = new StringBuffer();
        escape(s, sb);
        return sb.toString();
    }

    /**
     * @param s
     *            - Must not be null.
     * @param sb
     */
    static void escape(String s, StringBuffer sb)
    {
        for (int i = 0; i < s.length(); i++)
        {
            char ch = s.charAt(i);
            switch (ch)
            {
                case '"':
                    sb.append("\\\"");
                    break;
                case '\\':
                    sb.append("\\\\");
                    break;
                case '\b':
                    sb.append("\\b");
                    break;
                case '\f':
                    sb.append("\\f");
                    break;
                case '\n':
                    sb.append("\\n");
                    break;
                case '\r':
                    sb.append("\\r");
                    break;
                case '\t':
                    sb.append("\\t");
                    break;
                case '/':
                    sb.append("\\/");
                    break;
                default:
                    // Reference: http://www.unicode.org/versions/Unicode5.1.0/
                    if ((ch >= '\u0000' && ch <= '\u001F') || (ch >= '\u007F' && ch <= '\u009F')
                            || (ch >= '\u2000' && ch <= '\u20FF'))
                    {
                        String ss = Integer.toHexString(ch);
                        sb.append("\\u");
                        for (int k = 0; k < 4 - ss.length(); k++)
                        {
                            sb.append('0');
                        }
                        sb.append(ss.toUpperCase());
                    }
                    else
                    {
                        sb.append(ch);
                    }
            }
        }// for
    }

}
